With regard to a biological tissue such as the cardiac muscle, the objective and quantitative estimation of its functions is very important for the diagnosis of the tissue. In a routine examination of the heart by an ultrasonic diagnostic equipment and an ultrasonic image processing apparatus, there have been performed a volume measurement by a modified-simpson method using two-dimensional images obtained by apical approach (A4C (apical 4 chamber image), A2C (apical 2 chamber image) and the like) by two-dimensional scanning, and a measurement of an inner diameter shortening ratio (% FS) and a wall thickness from two-dimensional images obtained by extracting short axis images (SAX).
Further, a recent three-dimensional ultrasonic diagnostic equipment enables real time collection and display of three-dimensional ultrasonic images by scanning ultrasound beams in a three-dimensional manner. In addition, it has also been realized that arbitrary cross-sectional (Multi-planar Reconstruction: MPR) images are produced from collected three-dimensional image data and displayed. Then, the utilization of the MPR images enables the same various measurements as in the above conventional case.
However, in a case where the conventional ultrasonic diagnostic equipment and ultrasonic image processing apparatus are used to perform various measurements of the heart, for example, there are the following problems.
Firstly, when a cross-section of a vicinity of the heart apex is depicted in an apical approach image by use of two-dimensional scanning, it seems as if the heart apex portion can be depicted, even if the real heart apex position is not included within the scanned cross-section. Therefore, it is difficult to grasp a correct position of the scanned cross-section, and hence the heart apex portion cannot be correctly caught up in many cases. In addition, it also difficult that any one obtains, with an excellent reproducibility, the same apical approach images which pass through a correct central long axis. As the result, a volume measured underestimating a long axis length is underestimated, and such a case often occurs. Moreover, when the recognitions of the position of the heart apex portion for the depicted image are different among examiners, the measured values of volumes, EF and others are varied.
On the other hand, in a case where the cross-section of the vicinity of the heart apex is depicted in an apical approach image by use of three-dimensional scanning, the MPR image of the heart central long axis including the heart apex portion can be comparatively easily obtained. In this case, however, a spatial resolution and a temporal resolution are inferior to the case of the two-dimensional scanning. In consequence, an endocardial position relatively blurs by the restriction of the spatial resolution, and hence the position of an inner cavity is recognized to be more inside than in an actual case, whereby the volume is underestimated. In addition, the restriction of the temporal resolution relatively increases the variation of phases at the time of measurement, which deteriorates the reproducibility of the measurement results.
An object is to provide an ultrasonic diagnostic equipment and an ultrasonic image processing apparatus in which even a person who is not an expert can easily depict a reference cross-section by a correct two-dimensional scan which is necessary for the examination of the heart, and accuracy and reproducibility of a diagnosis using the reference cross-section can be enhanced.